OBJECTIVES: 1. SV40 DNA integration: Inverted repeat sequences of SV40 DNA has been mapped. The positions of these sequences correlate with integration sites of SV40 DNA into Ad2 genome. It is hypothesized that these sequences are used for general recombination and for integration. 2. SV40 RNA transcription: The primary transcripts of SV40 virus during lytic infection is studied using very short pulse. This is used to define the promoter, the termination and the size of the primary transcripts. The inverted repeat sequence of SV40 DNA also coincide with the 5' and 3' ends of the mRNA species. The role of these sequences in RNA processing is implied. 3. SV40 DNA protein complexes: Two forms of DNA-protein complexes were isolated. Complex I carries most of the biosynthetic activities. Complex II, derived from complex I is a stable intermediate in the synthesis of virions.